CN103323822B - Method and device for estimating channel errors - Google Patents

Abstract

The invention discloses a method and device for estimating channel errors. The method includes the steps that range direction fast Fourier transform is carried out on all channel data, and cross-correlation functions and range frequencies, in the azimuth direction, of the channel data after the transform are determined; phase positions of the cross-correlation functions are determined, and differential is carried out on the range frequencies; according to the phase positions of the cross-correlation functions and the differential results of the range frequencies, linear change rates of the phase positions of the cross-correlation functions along with the range frequencies are determined, and the linear change rates serve as delay errors among all the channels. The invention further discloses a device which is used for estimating the channel errors and achieves the method. By the utilization of the technical scheme, channel error estimating and compensation are carried out, the channel errors can be estimated accurately and rapidly, and imaging quality in SAR multi-beam imaging, interference imaging, moving target detection and the like is improved.

Description

A kind of method of estimating channel error and device

Technical field

The present invention relates to error determination technology, particularly relate to a kind of method and device of estimating channel error.

Background technology

Multichannel technology is at synthetic-aperture radar (SAR, Synthetic Aperture Radar) there is important application in the technology such as multi-beam imaging, interference imaging, moving target detect, it is one of key point of this technology that passage consistency compensates (mainly channel time delay and phase error), and therefore estimating channel time delay and phase error have important application value.

At present, channel time delay and phase error estimation method mainly contain internal calibration method and the method based on raw data.Method based on raw data mainly contains space-time adaptive filter method, Subspace Projection Method etc.In general, the precision of internal calibration method estimation time delay and phase error is high, but required number of devices more, the channel imbalance that antenna causes cannot be compensated, also cannot the change of tracker.Based on the method for raw data, do not need to increase number of devices and can compensate the change of channel imbalance that antenna causes and tracker, but current existing algorithm is complicated, and stability is bad.

In sum, how not increase on the basis of number of devices, accurately, stably estimating channel time delay and phase error are current problem demanding prompt solutions.

Summary of the invention

In view of this, fundamental purpose of the present invention is the method and the device that provide a kind of estimating channel error, can stablize, estimate exactly channel time delay and phase error.

For achieving the above object, technical scheme of the present invention is achieved in that

A method for estimating channel error, comprising:

Distance is carried out to Fast Fourier Transform (FFT) to each channel data, determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance;

Determine the phase place of described cross correlation function, differential is carried out to described frequency of distance;

The linear change rate of described cross correlation function phase place with described frequency of distance is determined, using described linear change rate as described each interchannel time delay error according to the phase place of described cross correlation function and the differentiation result of described frequency of distance.

Preferably, described method also comprises:

According to described time delay error, described each interchannel delay compensation is carried out to described cross correlation function, estimate described each interchannel phase error.

Preferably, described determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance, comprising:

Obtain the echo data of described each passage, distance is carried out to Fast Fourier Transform (FFT) process to described echo data, transform to distance frequency domain, orientation time domain;

Each channel signal after conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function; And, by each channel signal determination frequency of distance after the conversion of described distance frequency domain.

Preferably, described by conversion after each channel signal carry out cross-correlation along the orientation time, obtain orientation cross correlation function, comprising:

Each channel signal after described conversion is multiplied with reference signal conjugate;

Again by the related function after conjugate multiplication along orientation to integration, obtain orientation cross correlation function.

Preferably, described each channel signal after described conversion to be multiplied with reference signal conjugate, for:

$S_3(f_{\mathrm{\τ}},t)=S_1(f_{\mathrm{\τ}},t)\·S_2^{*}(f_{\mathrm{\τ}},t);$

Described by the related function after conjugate multiplication along orientation to integration, for:

$S_4=\left(f_{\mathrm{\τ}}\right)={\∫}_{-\∞}^{+\∞}{S}_3(f_{\mathrm{\τ}},t)\mathrm{dt};$

Wherein, S ₁(f _τ, t) represent channel signal, represent reference signal S ₂(f _τ, conjugation t), S ₃(f _τ, t) represent each channel signal be multiplied with reference signal conjugate after related function, S ₄(f _τ) represent cross correlation function.

Preferably, the differentiation result of the described phase place according to described cross correlation function and described frequency of distance determines that described cross correlation function phase place is with the linear change rate of described frequency of distance, comprising:

Obtain the phase place of described cross correlation function, and frequency of adjusting the distance carries out differential, average after the phase place of described cross correlation function and differentiation result are added, obtain described linear change rate.

Preferably, described by average after the phase place of described cross correlation function and differentiation result addition, for:

$\mathrm{\Δ\τ}=E\left\{\frac{d\arg \left(S_4\left(f_{\mathrm{\τ}}\right)\right)}{d{f}_{\mathrm{\τ}}}\right\};$

Δ τ represents interchannel linear change rate, and E{} represents and asks mathematic(al) mean, and arg () represents and goes phase place, f _τrepresent frequency of distance, S ₄(f _τ) represent cross correlation function.

Preferably, describedly carry out interchannel delay compensation according to gained time delay error pair correlation function, can phase error between estimating channel, for:

According to time delay error structural index item, the exponential term constructed is multiplied with distance frequency-region signal, carries out interchannel delay compensation according to time delay error;

Estimate the doppler centroid structural index item obtained according to systematic parameter or single-channel data, by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, and remove the phase contribution of the Doppler center in multiplied result;

The phase place of related function after the phase contribution obtaining delay compensation and remove the Doppler center in multiplied result, and along distance on average, calculate inter-channel phase error.

Preferably, the described exponential term according to time delay error structure is multiplied with distance frequency-region signal, for: S ₅(f _τ)=S ₄(f _τ) exp (-2 π f _τΔ τ);

Described by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, for:

$S_6\left(f_{\mathrm{\τ}}\right)=S_5\left(f_{\mathrm{\τ}}\right)\exp (-j2\mathrm{\π}{f}_d\frac{D}{2V});$

Describedly calculate inter-channel phase error, for:

Wherein, S ₅(f _τ) represent the related function after delay compensation error, f _τrepresent frequency of distance, Δ τ represents interchannel time delay, S ₆(f _τ) represent Doppler center compensate after related function, D represents two channel phases centre distances, and V represents platform speed, represent interchannel phase error.

A device for estimating channel error, comprises converter unit, the first determining unit, the second determining unit, differentiation element and the 3rd determining unit, wherein:

Converter unit, for carrying out distance to Fast Fourier Transform (FFT) to each channel data;

First determining unit, for determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance;

Second determining unit, for determining the phase place of described cross correlation function;

Differentiation element, for carrying out differential to described frequency of distance;

3rd determining unit, for determining the linear change rate of described cross correlation function phase place with described frequency of distance according to the phase place of described cross correlation function and the differentiation result of described frequency of distance, using described linear change rate as described each interchannel time delay error.

Preferably, described device also comprises compensating unit and estimation unit, wherein:

Compensating unit, for carrying out described each interchannel delay compensation according to described time delay error to described cross correlation function;

Estimation unit, for estimating described each interchannel phase error.

Preferably, described first determining unit also for, obtain the echo data of described each passage, distance carried out to Fast Fourier Transform (FFT) process to described echo data, transform to distance frequency domain, orientation time domain;

Each channel signal after conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function; And, by each channel signal determination frequency of distance after the conversion of described distance frequency domain.

Preferably, described 3rd determining unit also for, obtain the phase place of described cross correlation function, and frequency of adjusting the distance carries out differential, average after the phase place of described cross correlation function and differentiation result are added, obtain described linear change rate.

Preferably, described compensating unit also for, according to time delay error structural index item, by the exponential term constructed according to time delay error with distance frequency-region signal be multiplied, carry out interchannel delay compensation;

Estimate the doppler centroid structural index item obtained according to systematic parameter or single-channel data, by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, and remove the phase contribution of the Doppler center in multiplied result;

Described estimation unit also for, the phase place of related function after the phase contribution obtaining delay compensation and remove the Doppler center in multiplied result, and along distance on average, calculates inter-channel phase error.

In the present invention, when two antennas are along orientation to arrangement, jointly determined by channel error and Doppler center along distance frequency domain in the cross correlation function phase place of distance frequency domain, orientation time domain.This cross correlation function phase place is along the change of distance frequency domain approximately linear, change slope is determined by channel time delay, after removing linear change, its phase differential is determined jointly by Doppler center and channel phase errors, and Doppler center can be estimated to obtain according to systematic parameter or single-channel data.Therefore, two channel datas are first carried out distance to Fourier transform by the present invention, try to achieve conversion after data along orientation to cross correlation function; Extract the phase place of orientation cross correlation function and frequency differential of adjusting the distance tries to achieve the linear change rate of orientation cross correlation function phase place along frequency of distance, this i.e. interchannel time delay error; Time delay error pair correlation function according to obtaining carries out interchannel delay compensation, gets final product the phase error between estimating channel.Use technical scheme of the present invention to carry out channel error estimation and compensation, accurately, stably can estimate channel error, improve the image quality in the application such as the imaging of SAR multi-beam, interference imaging, moving target detect.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of the method for the estimating channel error of the embodiment of the present invention;

Fig. 2 is the process flow diagram of the method for the estimating channel error of application example of the present invention;

Fig. 3 is to cross-correlation phase diagram based on the orientation of the Three-channel data of Fig. 2;

Fig. 4 is the channel error compensation effect schematic diagram of application example of the present invention;

Fig. 5 is the composition structural representation of the device of the estimating channel error of the embodiment of the present invention.

Embodiment

Basic thought of the present invention is: carry out distance to Fast Fourier Transform (FFT) to each channel data, determine each channel data conversion after data along orientation to cross correlation function and frequency of distance; Determine the phase place of cross correlation function, frequency of adjusting the distance carries out differential; According to the phase place of cross correlation function and the differentiation result determination cross correlation function phase place of the frequency of distance linear change rate with frequency of distance, using linear change rate as described each interchannel time delay error.Time delay error pair correlation function according to obtaining carries out interchannel delay compensation, gets final product the phase error between estimating channel.

For making the object, technical solutions and advantages of the present invention clearly understand, by the following examples also with reference to accompanying drawing, the present invention is described in more detail.

Fig. 1 is the process flow diagram of the method for the estimating channel error of the embodiment of the present invention, and as shown in Figure 1, the method for the estimating channel error of this example comprises the following steps:

Step 101, does distance to Fourier transform to each channel data, try to achieve conversion after data along orientation to cross correlation function.

Particularly, carry out distance to the echo data of each passage obtained to process to Fast Fourier Transform (FFT) (FFT, Fast Fourier Transformation); Each channel signal after described conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function; Here, if adopt equation expression, then have:

$E\{S_1(f_{\mathrm{\τ}},t)S_2*(f_{\mathrm{\τ}},t)\}=r_0\left(\mathrm{\η}\right)\exp \left(j2\mathrm{\π}(f_d\frac{D}{2V}+f_{\mathrm{\τ}}\mathrm{\Δ\τ}+\mathrm{\Δ\φ})\right)$

Wherein, S ₁(f _τ, t), S ₂(f _τ, t) represent two passage echo datas (distance frequency domain, orientation time domain) respectively, * represents conjugation, and E{} represents and asks mathematic(al) mean, f _drepresent Doppler center, D represents two channel phases centre distances, and V represents platform speed, f _τrepresent frequency of distance, t represents the orientation time, and Δ τ represents two interchannel time delays, and Δ φ represents two interchannel phase errors.

Wherein, carrying out distance to the object of FFT process is: the multichannel echo data obtained is transformed to distance frequency domain, orientation time domain.

By each channel signal after conversion along orientation to when carrying out cross-correlation, can further include:

Each channel signal after described conversion is multiplied with reference signal conjugate, completes related operation; Again by the related function after conjugate multiplication along orientation to integration (being discrete addition in actual operation), obtain orientation cross correlation function; Here, if adopt equation expression, then have:

$S_3(f_{\mathrm{\τ}},t)=S_1(f_{\mathrm{\τ}},t)\·S_2^{*}(f_{\mathrm{\τ}},t)$

$S_4=\left(f_{\mathrm{\τ}}\right)={\∫}_{-\∞}^{+\∞}{S}_3(f_{\mathrm{\τ}},t)\mathrm{dt}$

Wherein, S ₃(f _τ, t) represent channel signal be multiplied with reference signal conjugate after related function, it is the function of frequency of distance and orientation time, S ₄(f _τ) representing orientation cross correlation function, it is the function of frequency of distance.

Step 102, obtain the phase place of orientation cross correlation function, and frequency differential of adjusting the distance tries to achieve orientation cross correlation function the phase place linear change rate with frequency of distance, linear change rate and interchannel time delay error.

Particularly, obtain the phase place of described orientation cross correlation function, and after frequency differential of adjusting the distance (actual operation is discrete differential computing), be added and on average namely obtain interchannel time delay; Here, if adopt equation expression, then have:

$\mathrm{\Δ\τ}=E\left\{\frac{d\arg \left(S_4\left(f_{\mathrm{\τ}}\right)\right)}{d{f}_{\mathrm{\τ}}}\right\}$

Wherein, Δ τ represents two interchannel time delays, and E{} represents and asks mathematic(al) mean, and arg () represents and goes phase place, f _τrepresent frequency of distance, S ₄(f _τ) represent orientation cross correlation function.

Step 103, carries out interchannel delay compensation according to obtained time delay error pair correlation function, gets final product the phase error between estimating channel.

Particularly, be multiplied with distance frequency-region signal according to obtained time delay error structural index item, carry out interchannel delay compensation; Estimate the signal multiplication after the doppler centroid structural index item that obtains and delay compensation according to systematic parameter or single-channel data again, remove the phase contribution of Doppler center; Obtain the phase place of related function after described operation, and along distance on average, calculate inter-channel phase error.

Wherein, described according to gained time delay error structural index item with distance frequency-region signal be multiplied, for:

S ₅(f _τ)＝S ₄(f _τ)·exp(-2π f _τΔτ)

Described according to the signal multiplication after doppler centroid structural index item and delay compensation, for:

$S_6\left(f_{\mathrm{\τ}}\right)=S_5\left(f_{\mathrm{\τ}}\right)\exp (-j2\mathrm{\π}{f}_d\frac{D}{2V})$

Described decorrelation function phase place, and along distance to being averaging, for:

Wherein, S ₅(f _τ) represent the related function after delay compensation error, f _τrepresent frequency of distance, Δ τ represents two interchannel time delays, S ₆(f _τ) represent Doppler center compensate after related function, D represents two channel phases centre distances, and V represents platform speed, represent the two interchannel phase errors estimating to obtain.

Below in conjunction with concrete example, the present invention is described in further detail again.

Fig. 2 is the process flow diagram of the method for the estimating channel error of application example of the present invention, below in conjunction with Fig. 2, and the process that the channel error describing this application example in detail is estimated.

First, carry out distance respectively to the echo data of each passage (passage 0 to passage 2) obtained to process to Fast Fourier Transform (FFT) (FFT).In the present embodiment, suppose that this receiving system has 3 passages, each channel data obtains distance frequency-region signal through distance after FFT.

Secondly, changes persuing change rear signal and reference signal along orientation to cross correlation function, in the present embodiment, choosing passage 1 signal is reference signal, and passage 0, passage 1 and passage 2 signal obtain two orientation cross correlation functions with it along orientation to cross-correlation respectively; The passage cross-correlation phase diagram that Fig. 3 (a) is is benchmark with passage 1, as shown in Fig. 3 (a), shows the phase diagram after three passage cross-correlation.

Then, extract the phase place of orientation cross correlation function respectively, and after frequency differential of adjusting the distance (actual operation is discrete differential computing), be added and on average namely obtain interchannel time delay.In the present embodiment, gained interchannel time delay is Δ τ ₀₁with Δ τ ₂₁.

Then, respectively interchannel delay compensation is carried out to orientation cross correlation function.In the present embodiment, delay compensation item is respectively: exp (-j2 π f _τΔ τ ₀₁) and exp (-j2 π f _τΔ τ ₂₁); Fig. 3 (b) is the channel phase errors figure after delay compensation, as shown in Fig. 3 (b), shows the channel phase errors after delay compensation.

Finally, the phase error between estimating channel, completes the estimation of channel error, and carries out error compensation accordingly.Method provided by the present invention, can be applicable in the imaging of SAR multi-beam, interference imaging, moving target detect etc.

Fig. 4 is the channel error compensation effect schematic diagram of application example of the present invention, and as shown in Figure 4, left figure is the result schematic diagram not doing channel error compensation, and right figure is the result schematic diagram adopting error compensation of the present invention; As seen from Figure 4, the present invention is used to carry out channel error estimation and compensation significantly improves image quality.

Adopt method provided by the invention, accurately, stably can estimate channel error.

Fig. 5 is the composition structural representation of the device of the estimating channel error of the embodiment of the present invention, as shown in Figure 5, the device of estimating channel error of the present invention comprises converter unit 50, first determining unit 51, second determining unit 52, differentiation element 53 and the 3rd determining unit 54, wherein:

Converter unit 50, for carrying out distance to Fast Fourier Transform (FFT) to each channel data;

First determining unit 51, for determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance;

Second determining unit 52, for determining the phase place of described cross correlation function;

Differentiation element 53, for carrying out differential to described frequency of distance;

3rd determining unit 54, for determining the linear change rate of described cross correlation function phase place with described frequency of distance according to the phase place of described cross correlation function and the differentiation result of described frequency of distance, using described linear change rate as described each interchannel time delay error.

On the basis of the device of the estimating channel error shown in Fig. 5, the device of the estimating channel error of this example also comprises compensating unit (not shown in Fig. 5) and estimation unit (not shown in Fig. 5), wherein:

Compensating unit, for carrying out described each interchannel delay compensation according to described time delay error to described cross correlation function;

Estimation unit, for estimating described each interchannel phase error.

Above-mentioned first determining unit 50 also for, obtain the echo data of described each passage, distance carried out to Fast Fourier Transform (FFT) process to described echo data, transform to distance frequency domain, orientation time domain;

Each channel signal after conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function; And, by each channel signal determination frequency of distance after the conversion of described distance frequency domain.

Each channel signal after conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function, comprising:

Each channel signal after described conversion is multiplied with reference signal conjugate;

Again by the related function after conjugate multiplication along orientation to integration, obtain orientation cross correlation function.

Described each channel signal after described conversion to be multiplied with reference signal conjugate, for:

$S_3(f_{\mathrm{\τ}},t)=S_1(f_{\mathrm{\τ}},t)\·S_2^{*}(f_{\mathrm{\τ}},t);$

Described by the related function after conjugate multiplication along orientation to integration, for:

$S_4=\left(f_{\mathrm{\τ}}\right)={\∫}_{-\∞}^{+\∞}{S}_3(f_{\mathrm{\τ}},t)\mathrm{dt};$

Wherein, S ₁(f _τ, t) represent channel signal, represent reference signal S ₂(f _τ, conjugation t), S ₃(f _τ, t) represent each channel signal be multiplied with reference signal conjugate after related function, S ₄(f _τ) represent cross correlation function.

Above-mentioned 3rd determining unit 54 also for, obtain the phase place of described cross correlation function, and frequency of adjusting the distance carries out differential, average after the phase place of described cross correlation function and differentiation result are added, obtain described linear change rate.

Average after the phase place of described cross correlation function and differentiation result are added, for:

$\mathrm{\Δ\τ}=E\left\{\frac{d\arg \left(S_4\left(f_{\mathrm{\τ}}\right)\right)}{d{f}_{\mathrm{\τ}}}\right\};$

Δ τ represents interchannel linear change rate, and E{} represents and asks mathematic(al) mean, and arg () represents and goes phase place, f _τrepresent frequency of distance, S ₄(f _τ) represent cross correlation function.

Above-mentioned compensating unit also for, according to time delay error structural index item, by the exponential term constructed according to time delay error with distance frequency-region signal be multiplied, carry out interchannel delay compensation;

Estimate the doppler centroid structural index item obtained according to systematic parameter or single-channel data, by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, and remove the phase contribution of the Doppler center in multiplied result;

Above-mentioned estimation unit also for, obtain the phase place of related function after described operation, and along distance on average, calculate inter-channel phase error.

Exponential term according to time delay error structure is multiplied with distance frequency-region signal, for: S ₅(f _τ)=S ₄(f _τ) exp (-2 π f _τΔ τ);

Described by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, for:

$S_6\left(f_{\mathrm{\τ}}\right)=S_5\left(f_{\mathrm{\τ}}\right)\exp (-j2\mathrm{\π}{f}_d\frac{D}{2V});$

Describedly calculate inter-channel phase error, for:

Wherein, S ₅(f _τ) represent the related function after delay compensation error, f _τrepresent frequency of distance, Δ τ represents interchannel time delay, S ₆(f _τ) represent Doppler center compensate after related function, D represents two channel phases centre distances, and V represents platform speed, represent interchannel phase error.

It will be appreciated by those skilled in the art that the practical function of each processing unit in the device of the estimating channel error shown in Fig. 5 can refer to the associated description of the method for aforementioned estimation channel error and understands.It will be appreciated by those skilled in the art that the function of each processing unit in the device of the estimating channel error shown in Fig. 5 realizes by the program run on processor, also realize by concrete logical circuit.

The above, be only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention.

Claims (14)

1. a method for estimating channel error, is characterized in that, described method comprises:

Distance is carried out to Fast Fourier Transform (FFT) to each channel data, determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance;

Determine the phase place of described cross correlation function, differential is carried out to described frequency of distance;

The linear change rate of described cross correlation function phase place with described frequency of distance is determined, using described linear change rate as described each interchannel time delay error according to the phase place of described cross correlation function and the differentiation result of described frequency of distance.

2. method according to claim 1, is characterized in that, described method also comprises:

According to described time delay error, described each interchannel delay compensation is carried out to described cross correlation function, estimate described each interchannel phase error.

3. method according to claim 1, is characterized in that, described determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance, comprising:

Obtain the echo data of described each passage, distance is carried out to Fast Fourier Transform (FFT) process to described echo data, transform to distance frequency domain, orientation time domain;

Each channel signal after conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function; And, by each channel signal determination frequency of distance after the conversion of described distance frequency domain.

4. method according to claim 3, is characterized in that, described by conversion after each channel signal carry out cross-correlation along the orientation time, obtain orientation cross correlation function, comprising:

Each channel signal after described conversion is multiplied with reference signal conjugate;

Again by the related function after conjugate multiplication along orientation to integration, obtain orientation cross correlation function.

5. method according to claim 4, is characterized in that,

Described each channel signal after described conversion to be multiplied with reference signal conjugate, for: $S_3(f_{\mathrm{\τ}},t)=S_1(f_{\mathrm{\τ}},t)\·S_2^{*}(f_{\mathrm{\τ}},t);$

Described by the related function after conjugate multiplication along orientation to integration, for: $S_4\left(f_{\mathrm{\τ}}\right)={\∫}_{-\∞}^{+\∞}{S}_3(f_{\mathrm{\τ}},t)\mathrm{dt};$

Wherein, f _τrepresent frequency of distance, t represents the orientation time, S ₁(f _τ, t) represent channel signal, represent reference signal S ₂(f _τ, conjugation t), S ₃(f _τ, t) represent each channel signal be multiplied with reference signal conjugate after related function, S ₄(f _τ) represent cross correlation function.

6. method according to claim 1, is characterized in that, the differentiation result of the described phase place according to described cross correlation function and described frequency of distance determines that described cross correlation function phase place is with the linear change rate of described frequency of distance, comprising:

Obtain the phase place of described cross correlation function, and frequency of adjusting the distance carries out differential, average after the results added of frequency differential that the phase place of described cross correlation function is adjusted the distance, obtain described linear change rate.

7. method according to claim 6, is characterized in that, the described phase place by described cross correlation function adjust the distance frequency differential results added after average, for:

$\mathrm{\Δ\τ}=E\left\{\frac{d\arg \left(S_4\left(f_{\mathrm{\τ}}\right)\right)}{{\mathrm{df}}_{\mathrm{\τ}}}\right\};$

Δ τ represents interchannel linear change rate, and E{} represents and asks mathematic(al) mean, and arg () represents and gets phase place, f _τrepresent frequency of distance, S ₄(f _τ) represent cross correlation function.

8. method according to claim 2, is characterized in that, describedly carries out interchannel delay compensation according to gained time delay error pair correlation function, can phase error between estimating channel, for:

According to time delay error structural index item, the exponential term constructed is multiplied with distance frequency-region signal, carries out interchannel delay compensation according to time delay error;

Estimate the doppler centroid structural index item obtained according to systematic parameter or single-channel data, by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, and remove the phase contribution of the Doppler center in multiplied result;

The phase place of related function after the phase contribution obtaining delay compensation and remove the Doppler center in multiplied result, and along distance on average, calculate inter-channel phase error.

9. method according to claim 8, is characterized in that, the described exponential term according to time delay error structure is multiplied with distance frequency-region signal, for: S ₅(f _τ)=S ₄(f _τ) exp (-2 π f _τΔ τ);

Described by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, for: $S_6\left(f_{\mathrm{\τ}}\right)=S_5\left(f_{\mathrm{\τ}}\right)\exp (-j2\mathrm{\π}{f}_d\frac{D}{2V});$

Describedly calculate inter-channel phase error, for:

Wherein, S ₄(f _τ) represent cross correlation function, f _drepresent Doppler center, E{} represents and asks mathematic(al) mean, S ₅(f _τ) represent the related function after delay compensation error, f _τrepresent frequency of distance, Δ τ represents interchannel time delay, S ₆(f _τ) represent Doppler center compensate after related function, D represents two channel phases centre distances, and V represents platform speed, represent interchannel phase error.

10. a device for estimating channel error, is characterized in that, described device comprises converter unit, the first determining unit, the second determining unit, differentiation element and the 3rd determining unit, wherein:

Converter unit, for carrying out distance to Fast Fourier Transform (FFT) to each channel data;

First determining unit, for determine the data after the conversion of described each channel data along orientation to cross correlation function and frequency of distance;

Second determining unit, for determining the phase place of described cross correlation function;

Differentiation element, for carrying out differential to described frequency of distance;

3rd determining unit, for determining the linear change rate of described cross correlation function phase place with described frequency of distance according to the phase place of described cross correlation function and the differentiation result of described frequency of distance, using described linear change rate as described each interchannel time delay error.

11. devices according to claim 10, is characterized in that, described device also comprises compensating unit and estimation unit, wherein:

Compensating unit, for carrying out described each interchannel delay compensation according to described time delay error to described cross correlation function;

Estimation unit, for estimating described each interchannel phase error.

12. devices according to claim 10, is characterized in that, described first determining unit also for, obtain the echo data of described each passage, distance carried out to Fast Fourier Transform (FFT) process to described echo data, transform to distance frequency domain, orientation time domain;

Each channel signal after conversion is carried out cross-correlation along the orientation time, obtains orientation cross correlation function; And, by each channel signal determination frequency of distance after the conversion of described distance frequency domain.

13. devices according to claim 10, it is characterized in that, described 3rd determining unit also for, obtain the phase place of described cross correlation function, and frequency of adjusting the distance carries out differential, average after the results added of frequency differential that the phase place of described cross correlation function is adjusted the distance, obtain described linear change rate.

14. devices according to claim 11, is characterized in that, described compensating unit also for, according to time delay error structural index item, by the exponential term constructed according to time delay error with distance frequency-region signal be multiplied, carry out interchannel delay compensation;

Estimate the doppler centroid structural index item obtained according to systematic parameter or single-channel data, by the signal multiplication after the exponential term that constructs according to doppler centroid and delay compensation, and remove the phase contribution of the Doppler center in multiplied result;

Described estimation unit also for, the phase place of related function after the phase contribution obtaining delay compensation and remove the Doppler center in multiplied result, and along distance on average, calculates inter-channel phase error.